A meta-analysis was conducted to determine the impact of physical activity on cognitive function improvement in patients with diabetes.
Hyperglycemia has been linked to decreased cognitive function, thus lowering the quality of life and impairing memory and language ability. In addition, patients that develop cognitive dysfunction have poor treatment adherence and an economic burden on the healthcare system. While physical activity improves glycemic control, it is controversial if this intervention can improve cognition. A few previous studies have shown that physical activity can reduce the risk of dementia, while some have shown no such association. However, studies that did not show an association included patients not adherent to physical exercise plans. Therefore, researchers did a meta-analysis of randomized control trials and cohort studies to assess the effect of physical activity on cognition in patients with diabetes.
Five studies were selected for inclusion in the meta-analysis after the exclusion of 4,336 articles. One study was a cohort study, and four studies were randomized control trials. The primary outcome was the change in cognition throughout the intervention. Similarly, the secondary outcome was the post-intervention cognitive score. A total of 2,581 patients with diabetes were analyzed, with 1,303 in the intervention groups and 1,278 in the control group. Interventions were aerobic exercise, resistance exercise, and non-aerobic exercise, with or without diet modifications. Therapies for the control group included monthly telephone calls, stretching, and gentle movement, and education. Study duration ranged from 12 weeks to 9.8 years, and sample sizes ranged from 47 to 1,091. Cognition was measured using MMSE (mini-mental state examination), MSE (mental state examination), or global cognitive score. In addition, researchers measured the effect with the standardized mean difference (SMD) of the change in cognition throughout the intervention duration between the control and intervention groups.
Pooled analysis found a significant improvement in cognitive function (SMD = 0.98, 95% CI, 0.34 – 1.62). No significant association was seen for the secondary outcome of post-intervention cognitive scores (SMD = 0.35, 95% CI -0.04 – 0.73). In the subgroup analysis, the cognitive function improvement was significantly greater in studies followed for less than one year (SMD = 2,14, 95% CI 1.63 – 2.64), with no difference in studies with follow-up times greater than one year. This may be due to lower adherence in patients with longer follow-up durations or worsening cognition over time. This study’s findings suggest that physical activity may reduce the risk of Alzheimer’s disease and dementia in patients with diabetes.
This study’s limitation is the varying cognitive tests, physical activity, and sample sizes used in the five studies included. Furthermore, publication bias was present, limiting the conclusion that an association between physical activity and cognition is present. However, cognitive improvement occurred in the patients after varying physical activity. A possible mechanism for this improvement is an increase in cerebral blood flow. Previous studies have shown a 40% decrease in cerebral blood flow in patients with Alzheimer’s disease compared to healthy patients in the control group. Another possible explanation is concerning b-hydroxybutyrate, a product in fat metabolism that improves neurodegenerative disease. As b-hydroxybutyrate levels increase, cognitive function is improved.
Moreover, aerobic exercise increases the production of myokines produced by the skeletal muscle, which improves blood flow to the brain. Although there are varying mechanisms, they all suggest that physical activity positively affects blood flow and improves cognitive function. Altogether, this study’s findings suggest that healthcare providers can play an essential role in preventing neurodegeneration by educating patients with diabetes on the importance of physical activity. In addition, clinicians should direct further attention towards the early implementation of lifestyle modifications.
- Physical activity leads to significant improvements in cognitive function for patients with diabetes.
- Physical activity should be implemented early on after diabetes diagnosis to prevent cognitive function worsening and subsequently affect adherence.
- Further studies are needed to determine the long-term impact of physical activity on cognition.
Wang, Ruitong et al. “The effect of physical activity interventions on cognition function in patients with diabetes: A systematic review and meta-analysis.” Diabetes/metabolism research and reviews, e3443. February 2, 2021.
Austin, Benjamin P et al. “Effects of hypoperfusion in Alzheimer’s disease.” Journal of Alzheimer’s disease: JAD vol. 26 Suppl 3, Suppl 3 (2011): 123-33.
Macrina Ghali, PharmD Candidate 2021, Florida A&M University, College of Pharmacy and Pharmaceutical Sciences